0
\$\begingroup\$

We are working on an LED dimmer circuit which supports DALI2.0 Interface. We already received the hardware and working on software only. LED driver circuit is based TPS92515HV and below is the circuitry enter image description here

But the issue is LED flickers when dimming below 3%. There is no Voltage-Current stability below 3%. Is it a problem with analog dimming. Hardware designers went to analog dimming decision after experimenting on both analog and PWM dimming and found PWM more prone to flickering. I'm not sure whether they have tried shunt FET dimming. What is the actual reason behind this issue and how to get rid of this?

\$\endgroup\$
  • 2
    \$\begingroup\$ What is the minimum load of your LED driver? \$\endgroup\$ – Joren Vaes Oct 3 '17 at 12:26
  • 1
    \$\begingroup\$ Most of the drivers in the market has a dimming range of 10-100%. \$\endgroup\$ – TheOne Oct 3 '17 at 12:41
  • 1
    \$\begingroup\$ Your circuit doesn't show how the LEDs are connected, what the LEDs actually are (data sheet required) and what the input supply voltage is. \$\endgroup\$ – Andy aka Oct 3 '17 at 12:43
  • 1
    \$\begingroup\$ @TheOne: Do you have any data on that percentage, or an explanation as to why? \$\endgroup\$ – Bort Oct 3 '17 at 12:51
  • 1
    \$\begingroup\$ There is no requirement in DALI standards for the minimum dimming level to be as low as that. As long as you set your Physical Min Level in your firmware appropriately for your circuit, you will not get complaints from a standards point of view. For example 3% would be 126 on the log curve. However, you may lose market share compared to the drivers that can go down to 1% (85 on the log curve). \$\endgroup\$ – Martin Oct 3 '17 at 13:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.